Method and device for positioning a workpiece

ABSTRACT

A device for positioning a workpiece includes a socket body rotatably held on a metallic ball by an array of permanent magnets arranged into a partial socket. An air delivery system controls a flow of air passing between the magnets and the ball to alter the friction between the socket body and the ball. A positive flow of air into the socket reduces the friction, allowing the workpiece to be more easily rotated during repositioning, whereas drawing air away from the socket produces a partial vacuum which increases the friction, causing the socket body to be locked in a single position on the ball.

FIELD OF THE INVENTION

The present invention broadly relates to devices for holding andpositioning parts and workpieces, and deals more particularly with amethod and device for positioning a workpiece using an air assisted,magnetic ball and socket.

BACKGROUND OF THE INVENTION

Various devices have been used in the past to hold and position objectssuch as parts and workpieces. Positioning devices are particularlyimportant in manufacturing environments where a workpiece beingassembled must be repositioned as a worker performs assembly or otheroperations on the workpiece. One example of the need for robustworkpiece positioners is found in the aircraft industry where manyassemblies are manufactured on manual assembly lines where workers mustorient and periodically reposition a workpiece to many differentpositions during assembly or other operations.

In the past, workpiece holders/positioners have been employed that arelimited in their ability to reposition a workpiece in all possiblepositions that might be required by an operator. In those cases where acomplete range of motion is provided for positioning a workpiece,relatively complex joints and linkages are necessary. Most workpiecepositioners that are relatively simple in construction pivot onlyapproximately 45 degrees about a central axis, while other, more complexpositioners are relief milled so that they can rotate up to 90 degreesin one restricted plane. However, even these prior art positioners donot always allow a workpiece to be positioned so that it is ergonomicand readily accessible by mechanics or assembly operators. Additionally,those prior positioners that are simple in construction are sometimeslimited in their ability to hold and position heavy loads.

Accordingly, there is a need for a workpiece positioner that is bothsimple in construction and allows a greater range of motion, up to 180degrees, without restriction. The present invention is directed towardssatisfying this need in the art.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, a device is provided forpositioning an object such as a part, comprising a body for mounting theobject on the device; an array of magnets carried on the body andspatially arranged form at least a partial socket; a ball at leastpartially rotatable within the socket and formed of a materialmagnetically attracted to the magnets; and, a compressed air deliverysystem for delivering compressed air to the interface between thesocket. The magnets are preferably permanent magnets spatially arrangedin a spherical section, and wherein adjacent magnets have alternatingnorth and south poles, respectively. The body may be integrally formedas by molding, with the magnets, or may be manufactured with a pluralityof cavities in which the magnets are later installed. The compressed airdelivery system may include one or more nozzles that introducecompressed air from a source to one or more channels formed in a surfaceof the body, contiguous to the socket. The introduction of compressedair into the socket reduces the force applied by the magnets to theball, thus allowing the workpiece to be more easily repositioned.

In accordance with another aspect of the invention, a device is providedfor positioning a workpiece, comprising a first portion including aspherical surface formed of a magnetically attractable material; asecond portion on which the workpiece may be mounted; a plurality ofpermanent magnets carried on the second portion for magneticallyattracting and holding the second portion on the first portion, thepermanent magnets being arranged to form a socket for receiving thespherical surface of the first portion, and wherein the first and secondportions are relatively rotatable to allow the workpiece to be moved anyof a plurality of positions; and, an air supply line communicating withthe socket for delivering a flow of pressurized air to the space betweenthe magnets and the spherical surface. The device also comprises asupport on which the ball is mounted, allowing the socket to berotatable around essentially the entire outer surface of the ball,providing nearly 180 degrees of range of motion for workpiecepositioning.

In accordance with another aspect of the invention, a device is providedfor holding a part in any of multiple positions, comprising a support; aspherical ball formed of magnetically attractable metal and held on thesupport at a ball support area; a mount for mounting the part on thedevice; an array of permanent magnets carried on the mount and spatiallyarranged to form a partial socket around a section of the sphericalball, the socket being sized such that the socket may be moved aroundthe entire spherical surface of the ball except for the ball supportarea. The device further includes a vacuum system including a vacuumline communicating with the partial socket for drawing air from the areabetween the magnets and the ball and urging the socket into tighterengagement with the ball, thereby locking the part in place.

In accordance with still another aspect of the invention, a method isprovided for positioning a workpiece, comprising the steps of: mountingthe workpiece on a body containing an array of magnets; arranging themagnets to form a socket on the body; mounting the socket on a metallicball; holding the socket on the ball using the magnetic force of themagnets; changing the friction between the magnets and the ball using aflow of air; and, positioning the workpiece to a desired position.

Various additional objects, features and advantages of the presentinvention can be more fully appreciated with reference to the detaileddescription and accompanying drawings that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an air assisted device for positioning aworkpiece, shown mounted on an assembly line trolley.

FIG. 2 is an enlarged, perspective view of the device shown in FIG. 1.

FIGS. 3 and 4 are perspective views of CAD representations of the deviceshown in FIG. 1.

FIG. 5 is a perspective view of a CAD representation showing thearrangement of the magnet array relative to the surface of the ball.

FIG. 6 is a cross sectional view of the device shown in FIG. 1,including an air flow control system for locking and releasing thepositioning device.

FIG. 7 is a fragmentary, bottom view of the socket body, showing airchannels for controlling air flow.

FIG. 8 is a cross sectional view of an alternate form of the socketbody.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIG. 1, the present invention relates to an airassisted positioning device generally indicated by the numeral 10, forpositioning or orienting a workpiece such as an aircraft fuselage panel14, in any of a multiplicity of ergonomic positions to allow an assemblyoperator or mechanic to work on the panel 14. Broadly, the device 10comprises a socket body 24 mounted on a ball 22 which is fixed to asupport 28. In the illustrated example, the support 28 comprises theoutput shaft of a pneumatically operated cylinder and slide assembly 20which controls the elevation of the panel 14. The slide assembly 20 ismounted on a wheeled trolley 16 guided along a track 18 which carriesthe panel 14 down an assembly line. The panel 14 is supported on amounting fixture 12, which in turn is fixed to the socket body 24. Thesocket body 24, and thus the panel 14, is rotatable 180 degrees, or morearound the entire surface of the ball 22, and is limited in rotationalmovement only by the support 28.

Referring now also to FIGS. 2-7, the ball 22 is spherical in shape andis formed of a metallic material having a large, positive magneticsusceptibility. Other suitable materials include, for example, iron,cobalt, nickel and alloys of these materials. These materials aresometimes referred to as being ferromagnetic.

The socket body 24 includes a lower body portion containing an array ofpermanent magnets 26 arranged such that adjacent ones of the magnets 26have alternating north and south poles. The socket body 24 includes anupper portion defining a mounting plate 30 on which a workpiece, orworkpiece holding fixture can be mounted. The socket body 24 comprisesnon-ferromagnetic material such as ABS, carbon fiber, nylon or othersynthetic material, formed by molding or machining. In the example shownin FIG. 6, the socket body 24 is integrally molded around the magnets26, and the mounting plate 30 is formed as a separate part which issecured to the molded socket body 24. The outer ends of the socket body24 surrounding the magnets 24 can be seen in FIG. 6 to engage or nearlyengage the ball 22, so as to create an almost air-tight socket cavity.Alternatively, however, as shown in FIG. 8, the socket body 40 can bemanufactured as a single part using rapid prototyping techniques such asSLS or FDM. The one-piece, socket body 40 shown in FIG. 8 has integrallyformed cavities 42 into which the magnets 26 may be inserted and fixedin place.

The permanent magnets 26 are held by the socket body 24 in an sphericalarray forming a partial socket. One end of each of the magnets 26contacts the spherical surface of ball 22. Although not shown in thedrawings, the outer ends or faces of the magnets 26 that contact theball 22 may be concave shaped so as to better conform to the sphericalsurface of the ball 22.

As best seen in FIG. 5, the magnets 26 are arranged in an array suchthat their relative positions maximize the magnetic flux which attractsthe ball 22. Although permanent magnets 26 are shown in the illustratedembodiment, it should be noted that electromagnets could alternately beused, although electromagnets would require wiring connections to asource of electrical power, in contrast to the simple constructionprovided by use of permanent magnets 26.

The semi-spherical, socket-like arrangement of the permanent magnets 26produce a sufficient attractive force between the socket body 24 and theball 22 to securely hold the panel 14 or other workpiece in the desiredposition. The socket body 24 may be rotated about the surface of theball 22, limited only by contact with the support 28. Thus, dependingupon the exact geometry and size of the socket body 24, the workpiececan be rotated 180 degrees or more.

In accordance with the present invention, the magnetic ball and socketpositioner described above is assisted by the selective introduction ofa flow of air between the interface of the ball 22 and the ends of themagnets 26 which contact the ball 22. As best seen in FIG. 6, an airnozzle 32 in the socket body 24 is connected with a pneumatic line 34 toa source of compressed air 36, or alternatively a vacuum. Compressed airsupplied from the source 36 through the nozzle 32 is introduced at oneor more openings 38 in the interior, concave shaped surface of thesocket body 24, facing the ball 22. The introduction of this flow ofcompressed air moves the magnets 26 slightly away from the ball 22,thereby reducing the contact friction in an amount that allows thesocket body 24, and thus the workpiece, to be more easily rotated to adesired position of orientation. When the workpiece has been so rotated,the compressed air supply is turned off, thus restoring the full levelof friction generated by the magnets 26, locking the workpiece in place.

In those applications where the workpiece may be particularly heavy, thevacuum source 36 may be used to withdraw air from the interface betweenthe ball 22 and magnets 26, creating a partial vacuum within the concavesocket body cavity which draws the magnets 26 more tightly intoengagement with the ball 22. The resulting, increased friction causesthe ball and socket to resist rotation more strongly. As shown in FIG.7, the concave inner surface of the socket body 24 surrounding the endsof the magnets 26 may be provided with grooves or channels 38 which aidin the distribution of air flow so that the compressed air (or vacuum)is applied more evenly over the entire socket area.

Although this invention has been described with respect to certainexemplary embodiments, it is to be understood that the specificembodiments are for purposes of illustration and not limitation, asother variations will occur to those of ordinary skill in the art.

1. A device for positioning an object such as a part, comprising: a bodyfor mounting the object on the device; an array of magnets carried onthe body and spatially arranged to form at least a partial socket; aball at least partially rotatable within the socket, and formed ofmaterial magnetically attracted to the magnets; and, a compressed airdelivery system for delivering compressed air to the interface betweenthe socket and the ball in order to selectively reduce friction betweenthe magnets and the ball.
 2. The device of claim 1, wherein the magnetsare permanent magnets spatially arranged in a spherical section.
 3. Thedevice of claim method of claim 1, wherein the magnets in the array arearranged such that adjacent magnets have alternating north and southpoles, respectively.
 4. The device method of claim 1, wherein: the bodyincludes a plurality of cylindrical cavities therein, and, the magnetsare cylindrical in shape and are fixed within the cavities.
 5. Thedevice of claim 1, wherein the magnets are integrally molded within thebody.
 6. The device of claim 1, wherein the body includes an exteriorsurface configured to have the object mounted thereon.
 7. The device ofclaim 1, further comprising: a source of compressed air; and, apneumatic delivery system for delivering compressed air from the sourceto a space between the magnets and the ball, the compressed air reducingthe friction between the magnets and the ball.
 8. The device of claim 7,further comprising: a vacuum source, a pneumatic delivery system fordrawing air from between a space between the magnets and the ball, andthe vacuum source, the vacuum increasing friction between the magnetsand the ball.
 9. A device for positioning an aircraft assembly,comprising: a first portion including a spherical surface formed of amagnetically attractable material; a second portion on which theassembly may be mounted; a plurality of permanent magnets carried on thesecond portion for magnetically attracting and holding the secondportion on the first portion, the permanent magnets being arranged toform a socket for receiving the spherical surface of the first portion,and wherein the first and second portions are relatively rotatable toallow the assembly to be moved to any of a plurality of positions; and,an air supply line communicating with the socket for delivering a flowof pressurized air to the space between the magnets and the sphericalsurface.
 10. The device of claim 9, wherein the first portion includes ametallic ball and the spherical surface portion is defined in the ball.11. The device of claim 10, wherein the device further comprises asupport, and the ball is mounted on the support at an area on theoutside surface of the ball, the socket being rotatable aroundessentially the entire outer surface of the ball outside the area wherethe ball is mounted to the support.
 12. The device of claim 9, whereinthe magnets are arranged in an array, and the poles of adjacent magnetsin the array alternate in polarity.
 13. The device of claim 9, wherein:the first portion includes a body having a plurality of cavitiestherein, and the magnets are respectively fixed within the cavities. 14.The device of claim 9, further comprising: at least one air passagewayin the first portion for allowing air to pass into an area between themagnets and the spherical surface.
 15. The device of claim 14, wherein:the first portion includes a spherical inner surface opposing thespherical surface of the first portion, and the air passageway includesa channel formed in the spherical inner surface.
 16. A device forholding a part in any of multiple positions, comprising: a support; aspherical ball formed of magnetically attractable metal and held on thesupport at a ball support area; a mount for mounting the part on thedevice; an array of permanent magnets carried on the mount and spatiallyarranged to form a partial socket around a section of the sphericalball, the socket being sized such the socket may be moved around theentire spherical surface of the ball except for the ball support area;and, an air delivery system for creating a flow of air within the socketthat changes the force required to rotate the mount relative to theball.
 17. The device of claim 16, wherein the air delivery systemincludes a source of compressed air and at least one channel in themount for delivering compressed air from the source to the socket, theflow of compressed air into the socket reducing the friction between thesocket and the ball.
 18. The device of claim 16, wherein the airdelivery system includes a vacuum source and at least one channel in themount for drawing air away from the socket, the flow of air away fromthe socket creating a partial vacuum in the socket that increases thefriction between the socket and the ball.
 19. The device of claim 16,wherein the air delivery system includes an opening in the mountcommunicating with the socket through which air may pass.
 20. The deviceof claim 16, wherein: the mount includes an interior, concave surface inwhich the magnets are received, and the air delivery system includes atleast one channel in the concave surface for distributing the flow ofair across the socket.
 21. A method of positioning a workpiece,comprising the steps of: (A) mounting a workpiece on a body containingan array of magnets; (B) arranging the magnets to form a socket on thebody; (C) mounting the socket on a metallic ball such that the magnetscontact and attract; (D) holding the socket on the ball using themagnetic force of the magnets; (E) changing the friction between themagnets and the ball using a flow of air; and, (F) positioning theworkpiece to a desired position.
 22. The method of claim 21, whereinstep (E) includes introducing a flow of compressed air into the socket,the compressed air urging the socket away from the ball and reducing thefriction between the magnets and the ball.
 23. The method of claim 21,wherein step (E) includes creating a partial vacuum within the socket tourge the socket toward the ball and increase the friction between themagnets and the ball.
 24. The method of claim 21, wherein the workpieceis a aircraft component.